Suspension of self-baking electrodes



' INVENTOR.

Jan. 11, 1944- G. HAGERUP-LARssEN SUSPENSION 0F SELF-BAKING ELECTRODESFiled April 17. 1945 3 Sheets-Sheet 1 [IH n mmm flaw' n Jan.A 11, l1944.

G. HAGERuP-LARssEN. 2,339,230 vSUS'PENSION F S'ELF-BAKING 'ELECTRODESFiled, April 1v, 194s :s sheets-sheet :s

PatentedJan. 1l, 1944 SUSPENSION or SELF-Baume Emcrnonas Georgllagerup-Larssen, New York, N. Y.. assignor to Det Norske Aktleselskabfor Elektrokemisk Industri, Oslo, Norway. a corporation ot NorwayApplication Aprn 17, 194s, sei-m No. 483,415

somma (ci. 1:-14)

The use of self-baking electrodes is now stand- 'ard in many plantswhere electrolytic processes are carried on, particularly in theproduction of aluminum. Such electrodes ordinarily are made ofrectangular shape and are quite large. 'I'he lower part of the electrodeis baked and hardened by the heat of the furnace and has substantialstrength, but the upper part of the electrode is in the formofa pastewhich has sumcient fluidity so as 'to exert a substantial hydraulicpressure tending to push out the sides of the electrode casing. To keepthe electrode casing from bulging under this pressure, it has been.customary to provide driven through appropriate holes made in the lside support beams, or these beams are arranged directly below the rowof contact pins. Heretof ore these support beams acting through a wholerow of contact pins have served also as a suspension means for theelectrode. Such an arrangement is shown for example in Torchet PatentNo. 2,073,356.

As the use of these self-baking electrodes has A steel beams placed'along the sides of the electrode and so to arrange them that as theelectrode steel framework surrounding the electrode well above the pointof consumption, which cooperates with a plurality of groupsof suspensionmembers which suspend the electrode from the support structure byattachment direct to the contact pins.

Each such group of suspension members comprises suspension members oftwo types.. One set or type is made up of movable suspension membetswhich are connected withappropriate mech-= anism so that they can belowered from time to time to feed the electrode toward the point ofconsumption. The other set of suspension mem.- bers, at least vone ofwhich is included in each group referred to, is adapted to be connectedto a contact pin near the' bottom of the electrode and'suspend theelectrode direct from the support structure so that the electrodecan beheld substantially immovable when the contact pins to which the movablesuspension members are connected are in approximately their bottomposition. Thus when the movable members have been lowered about as faras is feasible, the suspension members which serve as fixed supportshold the electrode against further movement. This connection should bemade manually at this time; lit is possible, but not practical inordinary operation to have this connection result from the xedsuspension members serving as a limit sothat when the electrode reachesa given position, the weight of the electrode is automatically s takenup by these iixed suspension members.

increased, the tendency of the art has been to i increase the size ofthe electrodes, and now they may be as large as 4 feet by 15 feet, oreven larger. When the electrode has a length (maximum horizontaldimension) in this order, the beams necesgary to act both to keep theelectrode in shape and to suspend it, become heavy and cumbersome anddemand the use oi substantial amounts of steel. for retaining theelectrode in shape but when these support beams are eliminated, themanner of suspending the electrode so that it can be fed downwardwithout interruption has oilered substantial diiilculties.

I have solved this problem by utilizing the fact that the strength ofthe electrode and its grip on the contact pins 'near the bottom is suchthat the electrode can` be suspended from not morel than half of thecontact pins in a given horizontal Other patents have disclosedmechanism row, and in many instances from as few as four such pins atone time. Utilizing this fact, I provide a suspension mechanism whichcomprises a Inany event, when the fixed suspension members aresupporting their contact. pins, the movable suspension members can bedisconnected and then raised and connected to an upper set of contactpins. The fixed connections are then released and disconnected from thecontact pins towhich they were connected and the suspension is againmade through the movable members, so that 'the electrode can be feddownward .as desired.

Various specitlc arrangements of the. two types of suspension members'ineach group can be had, but I prefer an arrangement whereby thesuspension members which serve as. the fixed supports canalso serve tosupport 'the electrode during its movement. I accomplish this bysupplying a i movablel beam along leach side of the electrode. Themovable suspension members are connected to these beams'- and the beamsin turn are con-v nected with appropriate' operating jacks. Thesuspension members which serve as. iixed supports pass through thesemovable beams and also 'through iixed beams higher up in the structure,support structure for the electrode. such as a al and are provided withappropriatestop devices,

l trode, but when the contact pins of the row carrying the load reachapproximately their bottommost position and the operator considers it istime to withdraw them, the top nuts are screwed down so that they willbear against the fixed support and prevent further downward movement otthe electrode. The suspension members which serve only as movablesuspension members are then disconnected from their contact pins and thenuts on the fixed suspension members which bore against the movable beamare screwed backsothatthesebeams canberaisedupuntil the movablesuspension members are in line with, and can be connected to an upperrow of contact pins. Ihe nuts at theA top of the supports can then beslacked on. releasing the fixed suspension members which can. bedisconnected from their contact pins and then drawn upwardly bytightening up the nuts bearing against the movable beam until they alsocan be connected to contact pins in an upper row and again become partof the movable suspension mechanism.

This type of arrangement is usually employed with the contact pins insuccessive rows being placed in staggered relationship, which means thatordinarily a set of movable suspension members and nxed suspensionmembers will be supplied for the diierent vertical rows of contact pins.

As an alternative construction, two- -sets of beams may be used, both ofwhich are movable, and each set being capable of being moved independentof the other. In such case one of these beams would serve as a movablesupport cooperating with one row of contact pins and the other wouldserve as the iixed support (cooperating with the next upper row ofcontact pins) to hold `pension is simplified by having the contact studsinserted into the electrode in pairs, thus employing one commonsuspension arrangement for two adjacent contact studs. In such case, asingie suspension member may run to a yoke forming a cradle supportingthe external end ci two contact studs.

By this arrangement the weight is automat ically distributed between thetwo xcd contact studs giving a very economical design. One movablesuspension can run to two of the studs and a iixed suspension can run toanother adjan` cent pair of studs. If this design is used with studs instaggered arrangement, the attachment to the short beam must be madeod-center so as not to interfere with the intermediate row of contactstuds. If the studs are placedin vertical rows and not staggered, thereis a tendency for the electrode to be weakened by the formation ofvertical cleavages and the electrical current may not be evenlydistributed. These diiilcultles can be overcome by driving in thecontact studs in pairs at different angles to a vertical planeperpendicular to the side of the electrode into which the pins aredriven. For example, the studs in one row may lie in a plane at theusual angle to the horizontal but at a deviation of 20 to the left of avertical plane perpendicular to the face of the electrode.' The studs inthe next row above .and the next row below may be positioned in asimilar manner but with a deviation of 20 to the right of suchperpendicular plane.

This invention may be readily understood by reference to theaccompanying drawings in which Fig. l is a side view oi a furnaceembodying my invention but broken through the middle to shorten thesame; Fig. 2 is a section on line 2-2 of Fig. 1; Fig'. 3 is an enlargeddetail of one of the suspension members with the suspension beam shownin section; Fig. 4 is a view of the part shown in Fig. 3 but taken atright angles; Fig. 5 is a detailed view of a modification, and Fig. 6 isa section on line 6 6 of Fig. 5.

In these drawings, the furnace I0 has mounted thereon a superstructurecomprising upright columns I2, a top framework I4 and fixed suspensionbeams I6. Toward each end of veach beam I6 is positioned a jack I8, andall four of these jacks are operated simultaneously by a common wheel20. jacks are shown in the drawingsA as the other two will be near theother end of the furnace, within the portion that is broken away and notshown in the drawings.

Suspended below the beams IB' are the movable beams 22 connected to thejacks I8 as indicated at 24. 'I'he beams 22 can be raised or loweredsimultaneously by the operation of the hand it becomes a solid electrodeat the bottom. Contact studs 28 are driven into the electrode massAthrough appropriate slots in the'casing 26. In

the example shown in Figs. 1 and `2 there are four rows of these contactstuds with the studs in alternate rows arranged in staggeredrelationship. The electrical connections to the contact studs 28 aremade through the bus bars 30 and the contact members 32 each of which ishere shown as` carrying four contact terminals for attachment to contactstuds as described in more detail in my copending application Ser. No.436,585.

The weight of the electrode (which may be as much as 26 tons) is, duringnormal operation, suspended from the movable beams 22 by alternatesuspension straps 34. It is highly desirable to have the weight oi theelectrodes carried by the contact studs near the bottom where theelectrode mass has the greatest strength. Accordingly these Contactstraps alternately sustain the electrode from those contact studs whichform the lowest row.

Asvillustrated in Figs. 3 and 4, the contact straps 34 are connectedthrough a yoke 36 with a rod 38. The rod 38 has anenlarged threadedportion 4U running through the movable beam 22, and this threadedportion" 4D is here shown as provided with a stop mechanism in the formof a nut 44 which in normal operation bears against the top surface ormovable beam 22.

It is to be noted that only two oi ther Certain of the suspension strapsll end with the enlarged portion 4I but others (and at least one neareach corner of the electrode) continues up through` the fixed beam Iland at its upper end is provided with a nut Il.

In Fig. l of the draw'irga'the device is shown in a normal position withthe beam 22 lowered part way down. Itwill be noted that in this case theweight of the electrode is carried by the contact studs in the secondand fourth vertical rows counting from the right hand end, and by thestuds in the third and fth vertical rows counting from the left handend. Of these, the suspension mechanism supporting the stud in thesecond row from the right and the suspension mechanism supporting thestud in the ilfth row from the left each terminates at the movable beam22, whereas the suspension mechanism for the stud's in the fourthrowfrom the right and in the third row from the left run up through the xedbeam I6.

When the time comes to withdraw a bottom row of contact pins, the nutsli above the beam IB are screwed down so that they will bear against theuppersurface of this fixed beam. A slight further downward movement ofthe movable beam 22 will then release all strain from that beam. Thecontact straps which are suscounting from the left hand end will bedrawn up against contact studs in the second horizontal row from thebottom to carry the weight of the electrode. 'I'he nuts I6 whichpreviously had carried the load are then slacked oil and thecorresponding suspension straps are loosened up and disconnected. Theserods are then lifted and the nuts u which Ahas been unscrewed are againscrewed back in place. I'he weight is then all carried by the second rowof studs from the bot- Itom and the bottom row of studs can be withdrawnand again inserted in the appropriate positions to form a new top row.The electrical connections usually are moved to an upper row of studsabout one day before the suspension straps are moved. This helps toinsure adequate strength.

By the arrangement shown the weight of the electrode is carried by arelatively large number of studs during normal operation and is carriedby a smaller number of studs during the change when the weight is beingtransferred from one horizontal row to the next. However', at all timesthe weight of the electrode is adequately taken care of Without risk ofimproper movement taking place. At the same time there are no heavybeams which need to be removed by hand from a bottom position and liftedup to a higher position, for the only beams that move` are those whichare operated by the hand wheel 20 which functions through'the jacks I8.

Itis obvious that as an alternative-method of operation when thechange-over is being made, instead of carrying the load on the contactpin in the fourth row from the right and in the third row from the left,the support mechanism cooperatingwiththecontactpininthethirdrow from theright and the fourth row from the left maybe drawn up to suspend theelect'rodefrom Y the nxed support beams it. "This is a somewhat 5 lessdesirable method of operation as the electrode is then being carried bya limited number of contact pins in an upper row where the strength ofthe electrode may not have fully developed.

InFigsrS and6 the studsZlaredriveninto 10 the electrode mass at the sameangle relative to the horizontal as before but instead of being drivenin parallel to a vertical plane perpendicular to the face of theelectrode, alternate rows of these studs are driven in at an angle tosuch vertical plane with the angles in Yalternate rows being reversed.This is clearly illustrated in' Fig. 6.

In this case. a movable suspension member comprises the yoke 5I havingtwo loops 52 each one of which embraces a contact stud. Theyoke 50 isconnected ,to a flexible cable 5l, so that it can be raised or loweredthrough the operation of a wheel 5i. In connection with the movable' xedbeam I6. This rod S equipped with a. nut' or similar stop mechanism 62.

With this constructionthe electrode is lowered with the weight carriedby the movable yoke 5I and the cable 5I until it reaches approximatelyits bottom-most position when the nut 62 is screwed down to engage thetop' of the beam I6.

The cable 54 is then slacked off slightly and the yoke 50 removed fromthe lower studs 28 and engaged around the two studs immediately aboveand the cable 5I is tightened until it is carrying the load. The nut i2is then slackened and screwed up far enough not to interfere withoperations and the yoke is moved up to the 40 next pair of studs. Asbefore, the bottom studs are withdrawn from the electrode as soon as thesuspension mechanism is removed from them and they are then driven in atthe top where the electrode material is comparatively soft.

By either of these arrangements the weight is applied to a row of studsonly when it is near the point where the electrode is consumed and whenthe electrode is thoroughly baked and hardened.vAshasalreadybeenstatemthsmaybe insured if a. day or two before theslpcnsion members are changed and two to three weeks after the studshave inially been driven into the electrodes, the electrical connectionsare changed to an upper row of contacts so that the ilow of electricalcurrent will give a final baking effect.

It has been found that when the electrodes are thoroughly baked. it maytake a force of as much as from l0 to 20 tons to pull-out a contact studwhere the contact stud has a diameter of about '10 mm. and is insertedfor a distance of approximately 300 mm. into the electrode. From this,plus the fact that it has been found that the electrode has suiilcientmechanicalY strength, 65 'it will be seen that four contact studs cancarry the weight of the electrode during the 'changeover even with verylarge electrodes that may l have a capacity of 45,000 amperes or more.Ob-

viously there should be at least four supports at any one time to givestabiilty. so that, as a practical matter, the total number ofsuspension members must be at least eight.

What I claim is:

1. AA.' suspension for self-baking 7i electrodes o1' the type described,comprising a pluralityv of contact studs driven into the sides of suchan electrode, xed support members, movable support members, and aplurality of suspension members, a part of which are adapted to connectcontact studs to the xed support members and a part of which are adaptedto connect contact studs to the movable support members, whereby theweight of the electrode may alternately be carried by the fixed supportmembers and by the movable support members.

2. A structure as specified in claim 1 in which contact studs areconnected to the movable support members during normal operation andmovement of the electrode, and in which studs are connected to the iixedsupport members while the suspension members connected to the movablesupport member are disconnected from the studs.

3. A structure as speciiied in claim 1, which includes a common movablesupport member for two adjacent contact studs, such support membercomprising a beam suspended at an intermediate point.

4. A structure as speciiied in claim 1 in which the suspension membersthat connect contact pins with the fixed support members are alsoadapted to connect contact studs to the movable support members whilethe electrode is being fed downwardly and are adapted to be disconnectedfrom the movable support members when a movable support member is beingmoved upwardly.

5. A structure as speciiied in claim 1 in which the suspension memberscomprise iiexible loops adapted to be hooked under the contact studs andin which the support members comprise beams running along the sides ofthe electrode.

6. A structure as specified in claim l in which the contact studs aredriveninto the electrode in horizontal rows with the studs in successiverows approximately above each other but at reversed angles relative to avertical plane at right angles to the face of the electrode into whichthe studs are driven.

7. A suspension mechanism for self-baking electrodes of the typedescribed, comprising a plurality of contact studs driven into the sidesof such an electrode and arranged in horizontal rows, a fixed supportstructure for the electrode and a plurality ofjg'roups of suspensionmembers adapted to suspend such electrode from such support structure byattachment to such contact studs, each group comprising at least twosuspension members, one of such suspension members being a movablemember adapted to be lowered from time to time to feed the electrodetoward the point of consumption and another of such members in eachgroup being adapted by direct connection between the iixed supportstructure and a Contact stud to assist in holding said electrode againstsubstantial movement when the contact studs to which the movablesuspension members are attached are in approximately their lowestposition, so that the electrode will be supported to permit the movablesuspension members to be disconnected from the contact studs in one rowand permit such movable suspension members to be connected to thecontact studs in a higher row, and means whereby such suspension membersholding the electrode against movement may -be released when the movablesuspension members are again connected to contact studs to support saidelectrode.

8. A suspension mechanism for self-baking electrodes of the typedescribed, comprising a plurality of contact studs driven into the sidesof such an electrode and arranged in approximately horizontal rows, twopairs of support members, a plurality of suspension members, at leastfour of which are adapted to connect contact studs to one pair of saidsupport members and at least another four of which are adapted toconnect contact studs to the other pair of said support members andmeans for moving at least one of said support members whereby the weightof the electrode may alternately be carried by said two pairs of supportmembers.

GEORG HAGERUP-LARSSEN.

